Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, People's Republic of China.
J Biol Inorg Chem. 2011 Jun;16(5):671-81. doi: 10.1007/s00775-011-0766-y. Epub 2011 Feb 27.
Experimental studies have demonstrated that oral administration of lanthanum chloride (LaCl(3)) inhibits the development of atherosclerosis, but the related mechanism has not been fully elucidated. Oxysterols are toxic to the vascular endothelial cells which are important in preventing the formation and progression of atheromatous plaque. In this study, we examined the effect of LaCl(3) on oxysterol cholestane-3β,5α,6β-triol (Triol)-induced apoptosis and the related mechanisms in ECV-304 cells, a presumptive endothelial cell line. Incubation with Triol resulted in apoptosis of ECV-304 cells, as determined by Hoechst 33342 staining, fluorescein isothiocyanate labeled annexin V/propidium iodide double staining, and the loss of mitochondrial membrane potential. Triol activated extracellular-signal-regulated kinase (ERK) and nuclear factor κB (NF-κB), and inhibition of Triol-activated ERK and NF-κB signaling by specific inhibitors attenuated apoptosis induction by Triol in ECV-304 cells. Pretreatment with LaCl(3) (1 μM) for 12 h before exposure to Triol decreased Triol-mediated apoptosis as well as activation of ERK and NF-κB. In addition, Triol induced oxidative stress in ECV-304 cells, manifested by the increase of intracellular reactive oxygen species generation and malondialdehyde level, and the reduction of the content of total protein thiols and the activity of antioxidant glutathione peroxidases; LaCl(3) pretreatment significantly reversed these effects. Finally, LaCl(3) pretreatment significantly inhibited the increases of intracellular Ca(2+) concentration induced by Triol. Our study suggests that Triol induced ECV-304 cell apoptosis, and LaCl(3) could suppress this effect probably by inhibiting intracellular Ca(2+) concentration elevation, oxidative stress, as well as activation of ERK and NF-κB signaling pathways.
实验研究表明，氯化镧（LaCl3）的口服给药可抑制动脉粥样硬化的发展，但相关机制尚未完全阐明。氧化固醇对血管内皮细胞有毒，而血管内皮细胞在防止动脉粥样斑块的形成和进展方面非常重要。在这项研究中，我们研究了 LaCl3对 ECV-304 细胞（假定的内皮细胞系）中氧化固醇胆甾烷-3β，5α，6β-三醇（Triol）诱导的细胞凋亡的影响及其相关机制。用 Hoechst 33342 染色、荧光素异硫氰酸酯标记的 annexin V/碘化丙啶双染色和线粒体膜电位的丧失来确定 Triol 处理导致 ECV-304 细胞凋亡。Triol 激活细胞外信号调节激酶（ERK）和核因子κB（NF-κB），而特异性抑制剂抑制 Triol 激活的 ERK 和 NF-κB 信号转导可减弱 Triol 在 ECV-304 细胞中诱导的细胞凋亡。在暴露于 Triol 之前用 LaCl3（1 μM）预处理 12 h 可降低 Triol 介导的细胞凋亡以及 ERK 和 NF-κB 的激活。此外，Triol 诱导 ECV-304 细胞氧化应激，表现为细胞内活性氧物种生成和丙二醛水平增加，以及总蛋白巯基含量和抗氧化谷胱甘肽过氧化物酶活性降低；LaCl3预处理显著逆转了这些作用。最后，LaCl3预处理显著抑制了 Triol 诱导的细胞内 Ca2+浓度增加。我们的研究表明，Triol 诱导 ECV-304 细胞凋亡，而 LaCl3可能通过抑制细胞内 Ca2+浓度升高、氧化应激以及 ERK 和 NF-κB 信号通路的激活来抑制这种作用。
